1. Field of the Invention
The present invention relates to an electrical traction system for automobiles that is a multifunction system integrating the main motor and brake generator function with the auxiliary charger and converter functions.
2. Description of the Related Art
In the field of the technology of electrical traction systems for automobiles, there is the major problem of reducing the quantity and cost price of the raw material used as well as the number of electronic components used for the controls.
The aim of the present invention therefore is to provide for an electrical traction system for automobiles that meets standard requirements more efficiently than do prior art traction systems of the same type, designed for the same purpose, notably inasmuch as this system is:
lighter, PA1 less costly, PA1 more efficient, PA1 more reliable, PA1 at least one electrical generator, notably an electromechanical generator (constituted, in this case, by a thermal motor for the driving of a generator, especially an AC motor) and/or an electrochemical generator, constituted by at least one accumulator and/or at least one fuel cell; PA1 at least one electrical motor that is reversible (namely a motor capable of working as a motor and brake generator and hence capable of carrying out the electrical traction in motor operation) said electrical machine being of the self-synchronous type, comprising: PA1 at least one charger carried in the system, said charger designed to recharge at least one main or auxiliary supply battery (Vp); PA1 at least one converter of the high-voltage direct current, corresponding to said main or auxiliary battery (Vp), into a low-voltage direct current designed for the supply and recharging of a standard power-supply battery (Vs), the voltage of which is notably 6 V or 12 V, PA1 the stator comprises star-connected first, second, third and fourth windings (E1, E2, E3, E4) that are spatially offset by 90/p mechanical degrees (2 p being the number of magnetic poles of the self-synchronous machine) and are connected two by two so as to define a first group and a second group of windings (E1, E2, E3, E4), of which the first group comprises said first and third stator windings (E2, E3) while the second group comprises said second and fourth windings (E2, E4) so that the windings (E1, E3) of said first group as well as the windings (E2, E4) of said second group are offset with respect to one another by 180 electrical degrees while the first and second windings (E1, E2) as well as the third and fourth windings (E3, E4) are offset with respect to one another by 90 electrical degrees; PA1 the above-mentioned switch-over means comprise first, second, third and fourth choppers (a, A, b, B) that are mounted in series respectively with said first, second, third and fourth windings (E1, E2, E3, E4) and are controlled sequentially two by two (a, A; b, B) during switching, i.e. the switching over of the first and second choppers (a, A) is actuated, then the switching over of the third and second choppers (b,A) as well as that of the third and fourth choppers (b, B), and this is followed by the switching over of the first and fourth (a, B), to enable the sequential shunting or routing of the stator current (Ist) in the stator windings combined two by two, i.e. respectively in the first and second windings (E1, E2), the third and second windings (E3, E2), the third and fourth windings (E3, E4), as well as in the first and fourth windings (E1, E4), said second and fourth choppers being also controlled in modulation to set the value of said stator current. PA1 in motor operation, said second and fourth choppers (A, B) are respectively protected by a first diode and a second diode, known as "free wheel"diodes (d1, d2) each connected in parallel with said first and second windings (E1, E2) and, respectively, said third and fourth windings (E3, E4); PA1 in generator operation, the reversal of the direction of flow of the current in the stator windings (E1, E2, E3, E4), with respect to the direction of flow of the current in motor operation, is controlled respectively by a third diode and a fourth diode (d3, d4) each series connected with said second winding (E2) and, respectively, said fourth stator winding (E4); PA1 the rotor current (Iro) in the rotor winding (E5) is controlled by a fifth one-way chopper (C) protected by a fifth diode (d5). PA1 the means for switching over from the motor/brake generator operation to the charger operation comprise: PA1 wherein said contacts (c1 to c5) make it possible to change the connections between the stator windings (E1, E2, E3, E4) and the corresponding electronic components in such a way that when said contacts work in the direction corresponding to the charger operation, they enable, by the opening of the first, second and third contacts (c1, c2, c3), firstly the series connection of said third and fourth stator windings (E3, E4) to each other to constitute the primary winding of a transformer and, secondly, the series connection of said first and second windings (E1, E2) to each other to constitute the secondary winding of said transformer while, by the closing and opening respectively of said fourth and fifth contacts (c4, c5), said first, second, third and fourth diodes (d1, d2, d3, d4) are connected to one another in such a way as to constitute the elements of a rectifier bridge connected to said secondary winding (E1+E2) of the transformer and designed to recharge the main or auxiliary battery, when the electromotive force is greater than the supply voltage; PA1 wherein the charging current of this battery is controlled in the primary winding (E3+E4) of said transformer by sixth and seventh choppers (D, E); and PA1 wherein a sixth contact (c6) which works in a closed state in motor operation mode and hence in an open state in the charger operation mode, provides, in conjunction with said second, third and fifth contacts (c2, c3, c5), for the insulation of the primary winding of the transformer from the secondary winding of said transformer, and hence insulates the mains supply from the battery (Vp).
and at the same time meets regulatory standards and especially safety standards.
The solution to the technical problem referred to here above is defined by means for the switching over of the stator windings of the electrical motor of the electrical traction system that is an object of the present invention enabling the performance, as required, by these same windings, of not only their main motor/generator function but also the auxiliary charger and/or converter functions.